Strip anti-loosening device



J1me 1964 F. J. RUSSELL ETAL 3,139,134

STRIP ANTI-LOOSENING DEVICE Filed April 25, 1961 INVENTOR. 17250 J RussE Z :paavaapr mini 660265 a. so; Oil/EFF By 3% g, f

ATTORNEYS United States Patent 3,139,134 STRIP ANTI-LOOSENING DEVICE Fred .l. Russell, 3300 Don Felipe Drive, Los Angeles, Calif. and George B. Soloviefi, South Gate, Qalifi; said 'Soloviefl assignor to said Russell Filed Apr. 25, 1961, Ser. No. 105,370 Claims. (Cl. 151-25) The invention relates to the provision of means for preventing the relative rotation of threaded members so that once a pair of threaded members have been screwed into threaded relationship they will resist an unscrewing operation except one which employs a positive rotating elfect to force the members to be unthreaded.

Although the device herein described is especially applicable to the retention of elements of a door lock, the same expedient is also generally useful in connection with the engagement of threaded elements such as nuts and bolts under circumstances where, during threading engagement and also during unthreading, it is desirable to be able to rotate the threaded elements with respect to each other against a moderate resistance, but without encountering a necessarily great amount of resistance.

In certain types of door locks heretofore in general use, the practice has been to provide a threaded engagement between the exterior portion of a relatively stationary sleeve-like element and the interior of a rose or escutcheon assembly in order to permit the rose or escutcheon assembly to be tightened against the surface of the door irrespective of whether the lock might be used upon a relatively thin door or a relatively thick door. In the devices of the kind made reference to, use has been made in the past of a resilient friction-creating device positioned in a recess in the extcriorly threaded element having flexible fingers extending outwardly so as to engage the corners of the threads of the interiorly threaded elements when the threaded elements are rotated into threaded engagement. The fingers exhibit a tendency to resist reverse rotation and deflection and accordingly provide a frictional resistance against unthreading of the parts.

In other areas of the art, the tendency has been to depend upon solid inserts, plugs, collars, and comparable elements usually of some yieldable synthetic plastic material, or on occasion fiber material, received in a suitable aperture in one of the threaded members which is either cut or deformed by the threads of the other member when in engagement, thereby to resist to some extent the rotation of one member with respect to the other.

Although the success of the locking operation in devices ot the last described type has been acceptable, the locking engagement is usually so tenacious that the parts cannot be readily separated. Also, particularly where solid plugs and like type of elements are employed, they are permanently cut and deformed once the threaded parts are rotated into engagement; and because of this, they deteriorate considerably and do not permit of extensive re-use. Further still, those devices heretofore employed for generating friction between threaded parts have needed some special preparation in one threaded part or the other to accommodate the plastic insert, making them poorly adapted to a great many desirable uses.

It is, therefore, an object of the invention to provide a new and improved anti-loosening device for threaded members which is resilient in character creating thereby a moderate amount of resistance to unthreading, but which does not bind or freeze the threaded parts together to such a degree but what they can be separated with reasonable ease.

Another object of the invention is to provide a new and improved anti-loosening device which is resilient in character, rather than solid, so that it can be deformed to a degree when the threaded parts are engaged and, by the tendency of the material to return to its initial shape, exert sufiicient force on the threaded parts to inhibit inadvertent loosening.

Still another object of the invention is to provide a strip type anti-loosening device for threaded parts of such character that one oft he threaded parts designed to receive it can be formed by a simple operation which additionally greatly improves the ease of insertion of the strip into position, thercby'to create an anti-loosening device which is relatively simple and inexpensive to manufacture and assemble.

Still another object of the invention is to provide a new and improved strip type anti-loosening device of resilient character arranged in such a relationship to the relatively threaded parts with whichit is used that neither the threads nor the resilient material will in no way be damaged, the strip type insert being one which moreover yields under pressure to generate the frictional resistance without permanent deformation and cutting, and which accordingly will last indefinitely despite the frequency with which the parts are threadedly engaged and disengaged.

With these and other objects in view, the invention consists in the construction, arrangement and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings.

FIGURE 1 is a longitudinal view showing the inner threaded element in elevation and the outer threaded element in section;

FIGURE 2 is a cross sectional view taken on the line 22. of FIGURE 1;

FIGURE 3 is a cross sectional view showing only the inner threaded part prior to engagement with the outer threaded part;

FIGURE 4 is a fragmentary longitudinal sectional View taken on the line 4-4- of FIGURE 1; and

FIGURE 5 is a side elevational view of a second form of the invention.

In an embodiment of the invention chosen for the purpose of illustration, there is shown in FIGURES 1, 2, 3, and 4 a pair of respectively male and female threaded members, namely, a male threaded member 10 and a female threaded member 11. In this particular embodiment, the threaded members are in the form of hollow annular members which is typical of certain types of devices wherein the invention is particularly useful, typical of these being attachment of a rose or escutcheon to a sleeve-like stationary portion of a door lock.

In the chosen embodiment, the male threaded member consists of a smooth-walled cylindrical section 12, a threaded section 13 consisting of a band of conventional helical external threads, and a flange 14. The Wall of the male threaded member, as is clearly apparent in FIGURES 2 and 3, is annular and defines an interior passage 15. It will be noted that the wall of the male threaded member has an appreciable thickness which is substantially greater than the depth of threads 16.

In the male threaded member is a slot 17 which extends transversely relative to the direction of the thread, and in the chosen embodiment is parallel to the longitudinal axis of the threaded member. The slot has a bottom 18 and an open top 19. The bottom is substantially greater in breadth than the breadth of the open top whereby there are formed undercut corners 20 and 21 at the inner ends of side walls 22 and 23.

mately one-twelfth of the circumference of the threaded section, and also one wherein the depth of the slot 17 is very roughly about one-fourth of the breadth. The suggested depth is, however, only by way of example although the depth should in any event be greater than the depth of the threads from the base to the apex.

It is also advantageous to have the slot 17 of length somewhat greater than the breadth of the band of male threads and extending beyond the outermost thread on each side. A convenient means of forming the slot is one which contemplates milling inwardly from one end of the male threaded member, as for example, the end adjacent the flange 14 and extending the slot thus formed a short distance beyond the thread at the opposite end of the band.

A strip or insert 25 is shown inserted in the slot 17. The insert is preferably in strip form and relatively thin in proportion to its breadth. A satisfactory material for the strip is a synthetic plastic material known by the trade name, Nylon, which has a relatively flexible, resilient character in sections of the thickness indicated. Various different grades and types of synthetic plastic materials are suitable, but the precise composition of the strip is not critical provided that it is flexible and resilient,

, and at the same time is relatively tough to a degree suffi cient to resist cutting by the threads.

The breadth of the strip 25 is somewhat greater than the breadth of the slot 17 between the corners 20 and 21 so that when the strip is inserted in the slot a longitudinal mid-portion 26 will be bowed resiliently outwardly to a location removed from the bottom 18 of the slot and extending far enough-outwardly to be slightly beyond, or

in any event not less than a distance even with the apex of the threads. Side edges of the strip are contained within the undercut corners and firmly retain the strip in position in the slot.

Because of constructing the slot in the manner indicated, namely, by cutting it inwardly from one end, the strip is easy to insert in the slot in that it can be started at one end, namely, the end adjacent the flange 14, by being forced into a bowed condition and slid into the slot until it spans the band of threads 16. Upon release the strip will be retained in the desired position in the slot, due to tension built up in the bowing of the strip.

The female threaded member 11 in the chosen embodiment consists of a sleeve section 28 having an inner cylindrical wall 29 substantially greater in diameter than the outside diameter of the threaded section 16, and therefore, leaving an annular clearance 33. An annular flange 30 of the female threaded member is relatively thicker and contains an internally threaded section 31, the breadth of which is less than the breadth of the band 16.

When the female threaded section 11 is applied over the male threaded section 10, the interior threaded section 31 threadedly engages the threaded section 13; and as it is rotated during the making of the threading engagement, the threads of the threaded section 31 press upon the longitudinal mid-portion 26 of the strip, depressing it as indicated in FIGURE 4 at the area between the edges, the eifect of which is to press it partially into the slot 17 The strip being resilient in character, resists to a degree the depressing action on the outwardly convex portion, the force of which tends to exert pressure between the interior and exterior threads on the opposite side of the members and throughout the threaded engagement to a degree sufficient to inhibit the free rotation of one with respect to the other, but not sufficient to freeze their threaded relationship. Because of the resiliency in the 4 strip and because it is sufliciently thin to avoid engagement of the strip with the bottom 18 of the slot during threaded engagement, the threads of the interior threaded section 31 will not cut into the strip but merely depress the strip to the extent indicated in FIGURE 4.

Conversely when the threaded members are disengaged, the resilience inherent in the strip 25 will again bow it outwardly to substantially the initial position where it is ready and capable of acting again in a similar fashion upon the next occasion when the members are threaded together. The flexibility and resiliency built into the strip by its character and its relationship to the slot 17 provides an anti-loosening device which need not be excessively cut or deformed in order to perform its intended purpose and is, therefore, one which can be used re peatedly.

In the form of the device illustrated in FIGURE 5, there is shown a bolt indicated generally by the reference character 35 which consists of a head 36 and threaded shank 37 consisting of a plurality of helical threads 38. The bolt is adapted to be engaged by a conventional nut 39.

A slot 40 is made in the shank 37 which may take substantially the same transverse cross sectional proportions and shape as the slot 17 heretofore described. In this instance, the width of the slot is somewhat smaller because of the smaller diameter of the shank 37. As shown, the slot 40 extends inwardly from a free end 41 of the shank toward the head 36 and may be stopped at any convenient location between the free end and the head.

A strip or insert 42 is used in the slot 40, the strip being of breadth greater than the breadth of the slot 40 so that it will be bowed outwardly in substantially the same fashion and proportion as indicated in FIGURE 3. The length of the strip 42 may, of course, vary in that it can extend throughout the full length of the slot 40 or a distance somewhat less than the length. The strip is inserted inwardly from the open end and can be pushed to a greater or lesser degree depending upon where it may be anticipated that the nut 39 will need its threaded engagement.

Should occassions arise where the strip might not be needed, it can be withdrawn from the slot and the nut then freely rotated in threaded engagement upon the shank 37 in a substantially conventional manner.

Although in both forms of the invention the slot has been shown cut in the exteriorly threaded or male threaded member, since locating the slot in that member has certain advantages, the novelty inherent in the resilient strip type anti-loosening device is likewise present to a comparable degree when the slot may be cut in the interior of the female threaded member instead of in the male threaded member.

While the invention has herein been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described the invention, what is claimed as new in support of Letters Patent is:

1. A threaded member adapted to threadedly engage another threaded member, said first identified threaded member having a slot extending in a direction transverse with respect to the threads, said slot having a depth greater than the depth of the threads, and an insert for said slot comprising a relatively flat strip of substantially resilient material having a width substantially greater than the width of the slot, said strip having both side edges interlocked in transverse pressure engagement with the sides of the slot substantially continuously along the length of the strip, both faces of the longitudinal mid-portion of the strip being bowed outwardly transversely with respect to the strip throughout substantially the entire length thereof in engagement with the threads and away from the bottom of the slot and toward the apexes of the threads of its member, said bowing being substantially uniformly along the length of the strip beyond the root diameter of the threads of its member, said strip being adapted to be depressed by the threads of the second identified threaded member to a position extending at least partially into the slot when the members are in threaded engagement whereby to inhibit relative rotation therebetween.

2. A threaded member adapted to threadedly engage another threaded member, said first identified member having a slot extending in a direction transverse with respect to the threads, said slot having undercut corners on opposite sides and having a depth greater than the depth of the threads, and an insert for said slot comprising a strip of substantially resilient synthetic plastic material having a length less than the length of the slot, the width of said strip being substantially greater than the width of the slot between said corners, said strip having side edges in transverse pressure engagement with the corners and initially having the longitudinal mid-portion bowed outwardly transversely of the strip away from the bottom of the slot and toward the apexes of the threads of its member by transversely acting pressure against opposite sides of the strip, the longitudinal mid-portion of said strip being depressed in a radial direction by the threads of the other of said threaded members partially into the slot when the members are in threaded engagement whereby to inhibit relative rotation therebetween.

3. A pair of respectively male and female threaded members having a threaded engagement with each other, one of said members having a slot extending in a direction transverse with respect to the threads, said slot having an inner side adjacent the base of the threads wider than the slot opening and forming thereby corners on opposite sides, said slot having a bottom extending between said corners at a depth greater than the depth of the threads, said slot having one end extending beyond the outermost thread of said one member, and an insert for said slot comprising a strip of substantially resilient synthetic plastic material having a length less than the length of the slot and a width greater than the width of the bottom of the slot, said strip being free of attachment to said one of said members and having side edges in transverse pressure engagement with the corners of the slot and having the longitudinal mid-portion bowed outwardly transversely of said strip toward the apexes of the threads of its member, said longitudinal mid-portion of said strip having a condition depressed by the threads of the other of said threaded members and extending inwardly into the slot when the members are in threaded engagement whereby to inhibit relative rotation between said members.

4. A pair of respectively male and female threaded members having a threaded engagement with each other, said male threaded member having a band of threads and having a slot extending in a direction transverse with respect to the threads, said slot having a bottom adjacent the base of the threads wider than the slot opening and forming thereby undercut corners on opposite sides, said slot having a depth greater than the depth of the threads and having one end extending beyond the outer most threads of said band of threads, and an insert for said slot comprising a strip of substantially resilient material having a length less than the length of the slot and an initial width substantially greater than the width of the slot between said corners, said strip having side edges in transverse pressure engagement with the corners of the slot and having the longitudinal mid-portion extendible resiliently outwardly, the longitudinal mid-portion of said strip being depressed by the threads of the female threaded member into a position extending at least partially into the slot when the members are in threaded engagement whereby to resist relative rotation therebetween in both directions.

5. In combination with a pair of respectively male and female threaded members wherein one of said members has a slot with side edges extending in a direction transverse with respect to the threads, an insert for said slot comprising a relatively flat strip of substantially resilient plastic material having a width greater than the width of the slot and a thickness less than the depth of the slot, said strip having side edges in interlocked positions of transverse pressure engagement with the side edges of the slot at fixed locations and substantially continuous along the length of the strip, both faces of a longitudinal portion of said strip intermediate the side edges extending away from the bottom of the slot and toward the apexes of the threads of its member, said strip being bowed over substantially the entire length thereof in engagement with the threads and projecting substantially uniformly along its length beyond the root diameter of the threads of its member, said strip being adapted to engage the threads of the other of said threaded members when the members are in threaded engagement.

References Cited in the file of this patent UNITED STATES PATENTS 447,697 Pollard Mar. 3, 1891 961,249 Meeker June 14, 1910 2,263,223 Protin Nov. 18, 1941 FOREIGN PATENTS 504,853 Great Britain May 2, 1939 

5. IN COMBINATION WITH A PAIR OF RESPECTIVELY MALE AND FEMALE THREADED MEMBERS WHEREIN ONE OF SAID MEMBERS HAS A SLOT WITH SIDE EDGES EXTENDING IN A DIRECTION TRANSVERSE WITH RESPECT TO THE THREADS, AN INSERT FOR SAID SLOT COMPRISING A RELATIVELY FLAT STRIP OF SUBSTANTIALLY RESILIENT PLASTIC MATERIAL HAVING A WIDTH GREATER THAN THE WIDTH OF THE SLOT AND A THICKNESS LESS THAN THE DEPTH OF THE SLOT, SAID STRIP HAVING SIDE EDGES IN INTERLOCKED POSITIONS OF TRANSVERSE PRESSURE ENGAGEMENT WITH THE SIDE EDGES OF THE SLOT AT FIXED LOCATIONS AND SUBSTANTIALLY CONTINUOUS ALONG THE LENGTH OF THE STRIP, BOTH FACES OF A LONGITUDINAL PORTION OF SAID STRIP INTERMEDIATE THE SIDE EDGES EXTENDING AWAY FROM THE BOTTOM OF THE SLOT AND TOWARD THE APEXES OF THE THREADS OF ITS MEMBER, SAID STRIP BEING BOWED OVER SUBSTANTIALLY THE ENTIRE LENGTH THEREOF IN ENGAGEMENT WITH THE THREADS AND PROJECTING SUBSTANTIALLY UNIFORMLY ALONG ITS LENGTH BEYOND THE ROOT DIAMETER OF THE THREADS OF ITS MEMBER, SAID STRIP BEING ADAPTED TO ENGAGE THE THREADS OF THE OTHER OF SAID THREADED MEMBERS WHEN THE MEMBERS ARE IN THREADED ENGAGEMENT. 